THE people in power don't always get it right, as well we all know. And Deputy Prime Minister John Prescott is sometimes perceived as getting it wrong more often than not, reports Phil Vaughan.

But you can't fault his judgment when it comes to cars - Jaguars are the very stuff deputy prime ministers are made of.

The people in power certainly seem to make the right choices when it comes to public and private transport, and Big John proudly carries the flag for one of the finest of Britain's motoring icons, Jaguar.

One particular model, the 4.2 litre Jaguar XJ8 long-wheelbase (LWB) Sovereign, has enough class to underpin anyone's political career, but with the build quality to outlast it.

The latest flagship Jaguar XJ Series has been out just a year, but the LWB Sovereign is the only version to venture into limousine territory, the aluminium bodywork stretched up to 5.21m, against the standard 5.09m XJ.

Understandably, in the land of all things large America - it has been extremely well received, and has helped boost Jaguar's sales performance in Europe, too.

A diesel joins the line-up this year, and it will be interesting to see just how well it is received - will XJ buyers trade down from a purring, even calming, growl to a harsher engine note?

The LWB's 4.2 litre, 300bhp engine looks to be putting up a strong argument for big-saloon supremacy, whisking the Sovereign smoothly to 60mph in just 6.3 seconds, and capable of 155mph tops. But this naturally-aspirated 4196cc V8 is towered over performance-wise by the supercharged LWB version, with output upped to 400bhp, and 1.3 seconds clipped off the 0-60mph sprint.

For travelling in magic carpet style, though, with the kind of ride comfort that goes with the lottery-win dream, the Sovereign is worth every last penny of the £60,370 asking price.

Push it, and it will perform effortlessly. Although the auto box has a manual facility, who wants to leave the luxury of do-it-all drive'?

And this superlative saloon was never destined for founding cornering cults, rear drive though it is.

Listing the amazing range of engine technology, suspension dynamics, and even braking and safety set-ups would take forever, and you need a double first in electronics and engineering to understand it all.

Rest easy, every traction, stability, braking, transmission and safety programme known to man is in there. Take the parking brake - it's electronic. The tiny lever needs only the gentlest of touches to operate - only if you find yourself having to do it, and the brake applies automatically when the key is removed.

As the Sovereign owner will probably spend more time sitting on the back seat, the optional powered, heated rear bench is a must, and a useful electric rear window blind is standard. But at least the poor chauffeur and bodyguard up front get heated, 16-way adjustment seats, and the heated, half wood/leather steering wheel is an absolute treasure on cold mornings.

The fitted cellphone, sited between the front seats, means either master or servant can use it, and the rear screen-media package, with feed-in sited in the centre armrest, brings 6.5-inch DVD screens sited in the front head-rests. Neat.

This XJ8 comes with a lot of standard kit seen on much cheaper premium cars, such as CD autochanger (boot mounted), navigation unit with touch-screen operation, cruise control, rain-sensing wipers, powered door mirrors, and front/rear parking warnings, but no-one, even at Sovereign prices, can match the environment of a big Jaguar.

All other interiors pale into sterility when matched against this cool cat. The ivory leather seating, with elegant contrast piping, backed by lashings of walnut veneer, help to create the car's tangible upper-crust cabin atmosphere.

And buyers in this price bracket certainly won't be troubled by mere details such as the group 18 insurance, and 26mpg combined fuel return.

Model: Jaguar XJ8 LWB Sovereign £60,370. XJ range from XJ6 3.0 (£39,970) to Super 4.2 LWB 4.2VR (£71,970).

Engine: 4196cc, 300bhp eight-cylinder engine, driving rear wheels through six-speed manual gearbox.

CO2 emissions: 264g/km.

Performance: Top speed 155mph, 0-60mph in 6.3 seconds.

Economy: City 17.7mpg, country 34.9mpg, combined 26mpg. Fuel tank: 76 litres.

Insurance group: 18.

Warranty: Three years/unlimited miles.